version: "1.0.2" name: devtools-layer-skilld description: "nuxtseo-layer-devtools shared devtools layer for Nuxt SEO modules. ALWAYS use when building, modifying, or reviewing devtools client code in any Nuxt SEO module. Consult for component API, composables, implementation patterns, or debugging devtools clients."

nuxtseo-layer-devtools

Shared components, composables, and design system for Nuxt SEO module devtools clients. Source: packages/devtools-layer/; package: nuxtseo-layer-devtools.

Available Libraries

Consumers get these without extra config:

• `@nuxt/ui` v4: UButton, UBadge, UIcon, UInput, UTooltip, UApp, and default variants from app.config.ts.
• `@vueuse/nuxt`: All VueUse composables auto imported.
• Shiki: loadShiki and useRenderCodeHighlight.

Architecture (Model C — source layer, assembled)

Each module ships a source layer under devtools/:

1. nuxtseo-shared/devtools discovers module layers, assembles one client, then serves each module at /__nuxt-seo-devtools/<slug>.
2. nuxtseo-layer-devtools supplies shared UI, composables, CSS, and fonts.
3. <module>/devtools/ supplies that module's pages and state. The assembler extends it with the base layer.

Rules

1. Module devtools/nuxt.config.ts contains export default defineNuxtConfig({}). Only register components when the module ships components/<mod>/.
2. Use EXPLICIT imports for layer composables — import { useDevtoolsConnection } from 'nuxtseo-layer-devtools/composables/rpc', import { appFetch } from '.../composables/rpc', import { isProductionMode, path, refreshTime } from '.../composables/state', import { loadShiki } from '.../composables/shiki'. Do NOT rely on auto-imports / #imports for layer composables (#imports is fine for Nuxt built-ins like navigateTo, useRoute, useAsyncData).
3. The module root tsconfig.json MUST exclude dist and devtools. Typecheck the devtools client only when assembled.
4. ALWAYS use layer components over custom HTML: DevtoolsSection not custom details, DevtoolsKeyValue not custom tables, DevtoolsSnippet/OCodeBlock not custom code blocks, DevtoolsPanel not a custom card, DevtoolsEmptyState/DevtoolsLoading/DevtoolsAlert not custom equivalents. Use KeyValueItem.code for inline code instead of separate snippets.
5. ALWAYS use @nuxt/ui components (UButton, UInput, UBadge, UIcon, UTooltip, etc.) for interactive elements. Never hand-roll a button/input/badge/tooltip.
6. NEVER add custom CSS that duplicates what the layer or Nuxt UI provides.
7. NEVER enable SSR in the client (it runs in an iframe) — the layer already sets ssr: false.
8. ALWAYS disable the module itself in the assembled client (the base layer sets robots: false, sitemap: false, content: false).
9. ALWAYS guard devtools setup with if (nuxt.options.dev) in module.ts; debug server routes are dev-only.
10. Debug endpoint convention: /__<module>__/debug.json (og-image is the historical exception: /_og/debug.json).
11. Use Carbon icons consistently (carbon: prefix). Give the debug tab devOnly: true; redirect dev-only tabs to the index in production via an isProductionMode watch.

Required File Structure

devtools/
├── nuxt.config.ts              # empty defineNuxtConfig({}) (+ components reg only if components/ exists)
├── pages/
│   ├── <mod>.vue               # DevtoolsLayout shell + <NuxtPage/> (REQUIRED)
│   └── <mod>/
│       ├── index.vue           # overview tab
│       ├── debug.vue           # devOnly tab
│       ├── docs.vue            # <DevtoolsDocs url=.../>
│       └── <other-tabs>.vue
├── lib/<mod>/
│   ├── state.ts                # data ref + refreshSources() + watch (REQUIRED)
│   └── rpc.ts                  # useDevtoolsConnection() (REQUIRED)
└── components/<mod>/           # OPTIONAL: module-specific UI only
src/
├── devtools.ts                 # wraps setupDevToolsUI from nuxtseo-shared/devtools
├── module.ts                   # setupDevToolsUI(dev only) + registers debug route
└── runtime/server/routes/__<module>__/
    └── debug.json.ts           # JSON debug endpoint

Implementation Templates

For full component/composable API reference, read reference.md.

devtools/nuxt.config.ts

// Assembled by nuxtseo-shared in the user's project; this extends the base layer there.
export default defineNuxtConfig({})

devtools/lib/<mod>/rpc.ts

import { useDevtoolsConnection } from 'nuxtseo-layer-devtools/composables/rpc'
// The layer's connection plugin already wires appFetch + route tracking and refreshes
// on connect; state.ts watches refreshTime to reload data, so no module host access here.
useDevtoolsConnection()

devtools/lib/<mod>/state.ts

import type { DebugData } from './types'
import { appFetch } from 'nuxtseo-layer-devtools/composables/rpc'
import { path, productionUrl, refreshTime } from 'nuxtseo-layer-devtools/composables/state'
import { ref, watch } from 'vue'
export const data = ref<DebugData | null>(null)
export async function refreshSources() {
  if (!appFetch.value)
    return
  data.value = await appFetch.value('/__<mod>__/debug.json', { query: { path: path.value } }).catch((error) => {
    console.warn('[nuxt-seo] failed to refresh debug data:', error)
    return null
  })
  if (data.value?.siteConfig?.url)
    productionUrl.value = data.value.siteConfig.url
}
watch([path, appFetch, refreshTime], () => {
  refreshSources()
})

devtools/pages/<mod>.vue (shell)

<script setup lang="ts">
import { isProductionMode } from 'nuxtseo-layer-devtools/composables/state'
import { computed, watch } from 'vue'
import { navigateTo, useRoute } from '#imports'
import { data, refreshSources } from '../lib/<mod>/state'
import '../lib/<mod>/rpc'
 
const route = useRoute()
const currentTab = computed(() => {
  const p = route.path
  if (p.startsWith('/<mod>/debug'))
    return 'debug'
  if (p.startsWith('/<mod>/docs'))
    return 'docs'
  return 'overview'
})
const navItems = [
  { value: 'overview', to: '/<mod>', icon: 'carbon:dashboard', label: 'Overview', devOnly: false },
  { value: 'debug', to: '/<mod>/debug', icon: 'carbon:debug', label: 'Debug', devOnly: true },
  { value: 'docs', to: '/<mod>/docs', icon: 'carbon:book', label: 'Docs', devOnly: false },
]
const version = computed(() => data.value?.runtimeConfig?.version || '')
 
watch(isProductionMode, (isProd) => {
  if (isProd && currentTab.value === 'debug')
    return navigateTo('/<mod>')
})
</script>
 
<template>
  <DevtoolsLayout
    v-model:active-tab="currentTab"
    module-name="nuxt-<module>"
    title="Title"
    icon="carbon:icon"
    :version="version"
    :nav-items="navItems"
    github-url="https://github.com/..."
    :loading="!data"
    @refresh="refreshSources"
  >
    <NuxtPage />
  </DevtoolsLayout>
</template>

DevtoolsLayout derives package updates and debug troubleshooting from module-name. Do not pass npmPackage or recreate troubleshooting.

src/module.ts (dev only)

if (nuxt.options.dev) {
  addServerHandler({ route: '/__<module>__/debug.json', handler: resolve('./runtime/server/routes/__<module>__/debug.json') })
  setupDevToolsUI(config, resolve)
}

Example:

For nuxt-sitemap, replace <mod> with sitemap; use /sitemap for the shell and /__sitemap__/debug.json for debug data.